Is Social Phobia Distinct from Avoidant Personality Disorder?

Avoidant Personality Disorder (AvPD) is generally considered a more extreme version of Social Phobia (SP). However, new research does not support this viewpoint and instead suggests that AvPD and SP are distinct types of General Social Phobia (GSP).

Lambe and Sunderland (2015) aimed to determine the differences between AvPD and SP, hypothesizing that there are “qualitative differences between AvPD and SP that are undermined by limiting research to participants with SP” (p. 115). Therefore, Lambe and Sunderland used three participant groups, AvPD only, SP only, and AvPD+SP to study the differences in conditions.

The term avoidant personality was initially considered a subcategory of the “traditional schizoid character rather than as part of the social phobia spectrum” (Millon, 1981, p. 116). There is overlap between SP and AvPD, as both conditions fall on a continuum based on severity of symptoms as well as function impairment. The lesser end of the spectrum is non-generalized social phobia (non-GSP) while the upper extreme is generalized social phobia (GSP). This classification aids in the categorization of AvPD as a more extreme version of SP. This viewpoint has been supported by many researchers and studies in the field of personality psychology and among studies of personality disorders.

After controlling for depression, differences in levels of self-esteem and anxiety were seen between SP only and AvPD+SP (Feske, Perry, Cambless, Renneberg, & Goldstein, 1996, p.116). This therefore supports categorizing AvPD separately from SP only, differing from most previous research. In Lambe and Sunderland’s study, SP was measured using the DSM-IV Axis I. AvPD screening was conducted by non-medical health professionals using the “ICD-10 anxious personality disorder as a proxy for AvPD” (Lampe & Sunderland, 2015, p. 127). This method of measuring AvPD is a major limitation of the study and can be problematic in terms of the study’s construct validity. However, both disorders were individually tested using the Composite International Diagnostic Interview (CIDI).

In spite of this issue of construct validity, the sample size was large with a diverse age range, which increases external validity and generalizability. 10,641 people responded to the National Survey of Mental Health and Wellbeing, a household survey distributed in Australia in 1997. From these 10,641 respondents, 381 were chosen to participate in this current study, which asked background questions about age, sex, marital status, level of education, and employment status. The NSMHW survey also examined suicidal thoughts and attempts, as well as meetings with mental health professionals (Andrews, Henderson, & Hall, 2001, p. 117). These factors were important for determining the presence of comorbid disorders such as depression, which could greatly effect results.

In Lampe et al.’s (2003) study, six specific social situation questions were deemed significant for determining AvPD by means of the ICD-10. However two screening questions were removed for this current study because they lacked “a specific relationship to interpersonal anxiety” (Lambe & Sunderland, 2015, p. 118). This reanalysis in classifying AvPD is important for current and future studies; however, it raises doubt about previous theory and testing methods that included questions that are too general and/or are about unrelated topics. This is especially apparent in determining the presence of AvPD because it previously required that three out of six specific social situations caused GSP; however, in this study, after removing two of the six questions, one must feel GSP in 75% of the situations compared to the usual 50% of situations.

The results supported Lambe and Sunderland’s hypothesis that SP and AvPD are distinct types of General Social Phobia, instead of AvPD being a more extreme version of Social Phobia. Those with SP only had significantly lower suicidal thoughts compared to SP+AvPD, while there was no difference between AvPD and SP+AvPD or AvPD only and SP only in suicidal ideation. Therefore, the comorbidity of SP+AvPD increases suicide attempts 25% (p. 121-122). Additionally, the average number of feared social situations and reported 12-month depression were greater for those with comorbid SP and AvPD.

These findings raise questions about previous theory that Social Phobia and Avoidant Personality Disorder are on a continuum of the same disorder. This is up for debate because this research supported the separation of SP and AvPD. While there are potential operationalization problems with this study and in the future should be conducted using a longitudinal design, it provides different findings that are significant to understanding social phobia and avoidant personality disorders. A strong comprehension of SP and AvPD is important in understanding personality disorders and developing this field of study.